Due to having advantages such as easy-to-operation, in recent years touch devices have been widely used in a variety of electronic products, such as mobile phones, digital cameras, music players, tablet computers, satellite navigation devices and touch panels. Basically, the present touch devices can be categorized to: resistive type, capacitive type and optical type. Because having a relatively better durability and a lower cost, optical touch devices accordingly have drawn more and more attention.
FIG. 1 is a schematic structure view of a conventional optical touch device. As shown, the conventional optical touch device 100 includes a light guide assembly 110, a light emitting component 120 and a light sensing component 130. The light guide assembly 110 includes two light guide strips 112a, 112b and a reflective mirror 114. The light guide strips 112a, 112b and reflective mirror 114 are arranged respectively along three of four sides of a rectangular trajectory. In particular, the light guide strip 112a and the reflective mirror 114 are disposed to be opposite to each other; the light guide strip 112b is disposed to be connected between the light guide strip 112a and the reflective mirror 114; and the area within the rectangular trajectory is defined to as a sensing area 116 of the optical touch device 100. The light emitting component 120 is disposed between the adjacent two ends of the light guide strips 112a, 112b and configured to provide light into the light guide strips 112a, 112b. The light guide strips 112a, 112b each are configured to convert the light, provided from the light emitting component 120, into a linear light source for the entire sensing area 116. In addition, the light sensing component 130 is disposed adjacent to one end of the light guide strip 112a. 
The light sensing component 130 is configured to detect a light blocking object (for example, a user's finger) in the sensing area 116 and determine the light blocking object' position in the sensing area 116. Specifically, if a touch point (or, a light blocking object) A is located in the sensing area 116, a corresponding mirror point Al will be formed on the reflective mirror 114 and accordingly a dark point A2, derived from the touch point A, and a dark point A3, derived from the mirror point A1, are generated. As such, through the light sensing component 130 detecting the dark points A2, A3 so as to obtain the optical information thereof, the position of the touch point A in the sensing area 116 can be determined. The means for the determination of a touch point's position are apparent to those ordinarily skilled in the art, and no any unnecessary detail will be given here.
FIG. 2 is a schematic cross-sectional view of the optical touch device in the FIG. 1 along a line I-I. Please refer to FIGS. 1, 2. The reflective mirror 114 in the conventional optical touch device 100 has a reflective surface 117, which is a flat mirror surface and configured to reflect light 122, and a bottom surface 118, which is designed to be parallel to a plane (for example, a XY-plane) defined by the X-axis and Y-axis. However, as illustrated in FIG. 2, if a bearing substrate (not shown) configured to support the optical touch device 100 bends and thereby resulting in the bottom surface 118 of the reflective mirror 114 not being parallel to the XY-plane, the light 122′, derived from the light 122 and reflected by the reflective surface 117, may not successfully emit into the area capable of being sensed by the light sensing component 130. Thus, the optical touch device 100 may not work properly.
For solving the above problem, the reflective mirror 114 can be replaced by the reflective mirror 140 shown in FIG. 3. As shown, the reflective mirror 140 has a light incident surface 142 and a plurality of reflective pillars 143; in particular, the light incident surface 142 is opposite to the reflective pillars 143. Each reflective pillar 143 has, for example, a triangular structure and protrudes away from the light incident surface 142. Through this specific structure of the reflective pillar 143, the light 122′, emitted out from the reflective mirror 140, can be adjusted to be parallel to the light 122, to be emitted into the reflective mirror 140 on a plane (for example, a YZ-plane) defined by the Y-axis and Z-axis, so as to prevent the associated optical touch device from working improperly resulted from a bent bearing substrate.
Basically, the reflective mirror 140 can be produced by either an injection molding mean or an extrusion molding mean. However, if the injection molding mean is employed, the various-sized reflective mirror moulds for the production of various-sized optical touch devices are required and accordingly a relatively high mould cost is resulted in. Alternatively, if the extrusion molding mean is employed, a reflective pillar 143 having a shape not qualified for requirements may be produced. For example, the top-angle θ 1 of the reflective pillar 143 may not exactly equal to 90 degrees; and thus, the reflective mirror 140 may have an affected light reflection effect.